Suit Fabric Explained: Super Numbers, Wool Grades & What to Buy

When you're spending serious money on a suit, understanding what you're buying matters. The label might say Super 150s or 100% wool - but what does that actually mean for how the suit looks, feels, and lasts?

This guide cuts through the jargon so you can make a more informed choice.

What Are Super Numbers?

The Super number - Super 100s, 120s, 150s, 180s, 200s - refers to the fineness of the individual wool fibres used to weave the cloth. Specifically, it measures the diameter of the fibre in microns: the higher the number, the finer the fibre.

• Super 100s–110s: Robust everyday workhorse cloths. Slightly coarser to the touch but extremely durable. Excellent for suits worn frequently or in demanding environments.
• Super 120s–130s: The sweet spot for most men. Fine enough to drape beautifully and feel soft against the skin, while remaining resilient enough for regular wear. This is where most well-regarded Italian tailoring houses work.
• Super 150s–160s: Noticeably silkier and lighter. These cloths have a luminous quality that photographs brilliantly. Ideal for special occasions, weddings, or business meetings where appearance is paramount - but they require more careful handling.
• Super 180s–200s and beyond: The pinnacle of woven cloth. Extraordinarily fine, with a liquid drape and extraordinary lustre. These are statement fabrics for those who know exactly what they want and how to care for it.

A practical rule: if you're buying your first or second quality suit, aim for Super 120s–130s. You'll get the refinement without sacrificing longevity.

Weight: The Other Critical Factor

Super numbers tell you about fibre fineness. Fabric weight - measured in grams per linear metre (g/m) - tells you about substance and seasonality.

• Under 250g/m: Lightweight summer cloths. Cool and breathable, but they crease more readily.
• 270–310g/m: The year-round middle ground. Works across three seasons in the British climate.
• 320–380g/m and above: Autumn/winter weight. Structured, warmer, and more forgiving of creasing.

A Super 150s cloth at 260g/m is a very different proposition from a Super 150s cloth at 340g/m. Both are high quality - but one is a summer suit, the other an autumn suit.

Wool Blends Worth Knowing

Pure wool remains the benchmark - it breathes, presses well, and ages gracefully. But several blends are worth understanding:

• Wool/silk: Adds a subtle sheen and reduces weight. Common in high-end dress cloths.
• Wool/linen: Introduces texture and a relaxed, seasonal character. Very much a summer and warmer-weather cloth.
• Wool/cashmere: Softer hand than pure wool, with a slight lustre. A popular choice for jackets and odd trousers as well as suits.

Avoid suits with synthetic content above 5% if longevity and breathability matter to you. Polyester blends resist creasing but rarely age well or hold a press.

Cloth Origin: Does It Matter?

The finest suit cloths in the world come from a small number of mills - predominantly in the Biella region of northern Italy and the towns of Huddersfield and Hawick in the UK. Names like Loro Piana, Zegna, Vitale Barberis Canonico, and Dormeuil are reliable markers of quality.

Italian mills tend toward lighter, more fluid cloths with a refined finish. British mills - particularly the Yorkshire houses - produce slightly denser, more structured cloths with exceptional durability. Neither is categorically superior; it depends on the aesthetic and occasion.

What This Means When You're Buying

Rather than chasing the highest Super number, ask these questions:

1. How often will I wear this suit? (Daily wear = lower Super number, higher weight)
2. What season is it primarily for?
3. What occasions will it serve? (Formal events reward finer cloths; working suits reward robustness)
4. Can I care for it properly? (Finer cloths need gentler handling and proper storage)

A Super 120s suit in a 290g/m cloth from a reputable Italian mill, well constructed and properly cared for, will outlast and outperform a Super 180s suit treated carelessly.

Shop the Edit

At Richard Gelding, we work with makers who take cloth selection seriously. Browse our tailoring from Canali - one of Italy's most respected tailoring houses - and Ring Jacket, whose Japanese craftsmen work exclusively with premium Italian and British cloths. For the full range of tailored clothing, explore our Clothing collection.

If you'd like guidance on choosing the right suit for a specific occasion or budget, feel free to get in touch - considered advice is part of what we offer.